JP4136468B2 - Wireless communication terminal, wireless communication method, and program - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to mobile communication.
[0002]
[Prior art]
As this kind of invention, for example, a mobile satellite communication system described in Japanese Patent Laid-Open No. 7-154856 is known. In this system, the position detection means for the mobile terminal device to detect the current position, the map database including the line-of-sight map information indicating the position where communication with the communication satellite is possible, and communication with the communication satellite by the current position and the line-of-sight map information A communicable time zone predicting means for predicting a possible time zone is provided.
[0003]
Also, this mobile terminal device stores information to be transmitted in the transmission information storage means until the communicable time zone is reached, and transmits the information to be transmitted in the time zone predicted to be communicable. For this reason, this mobile terminal apparatus improves the operating rate of the mobile satellite communication system in an area where shadowing for communication satellites occurs in a complicated manner, such as an area where buildings in a city are densely packed.
[0004]
In this prior art, consideration is given to the mobile terminal to transmit transmission information efficiently. That is, since the transmission time can be controlled depending on the circumstances on the transmission side, as long as there is an empty area in the transmission information storage unit, it is possible to search for a time when transmission can be performed efficiently.
[0005]
On the other hand, in this prior art, there has been no recognition of the problem in receiving information. That is, in mobile communication, it is necessary to efficiently receive information from a communication partner as in the case of transmitting information from a mobile body. In that case, the mobile body on the receiving side cannot recognize whether or not the information is actually transmitted when the communication partner can communicate.
[0006]
For example, in the field of automobiles, various developments are being promoted to realize an intelligent transport system (hereinafter referred to as ITS). In ITS, for example, a terminal in a car is equipped with a communication function, and a fee collection function, various information, or the like by ETC (Electronic Toll Collection), DSRC (Dedicated Short Range Communication), VICS (Vehicle Information Communication System) Services and the like are provided via signals from roadside devices, electromagnetic waves from base stations, and the like (hereinafter referred to as wireless media).
[0007]
Such a function, information, or service is limitedly provided in a range in which a signal from a roadside device, a base station, or the like can be received (referred to as a wireless communication zone or a spot area). Therefore, conventionally, it has been necessary to constantly monitor such a wireless communication zone. However, in a spot service such as an ETC service, the wireless communication zone in which wireless communication is possible is very narrow, and the stay rate in the zone is very small.
[0008]
Also, these functions, information, or services are generally provided constantly or repeatedly at a predetermined cycle. However, among these functions and services, there are those in which the repetition cycle provided for the convenience of the provider is set longer or the provision is suspended.
[0009]
Therefore, whether or not information can be received or service can be received cannot be determined on the receiving side simply based on whether or not communication is possible. For this reason, there is a case where efficient communication is not always possible in communication by a mobile body. For this reason, although the actual communication time is limited to a short time, the load of the monitoring process for the wireless medium has been increased. Further, such monitoring processing has been a factor in increasing power consumption.
[0010]
[Problems to be solved by the invention]
The present invention has been made in view of such problems of the conventional technology. That is, the subject of this invention is providing the communication function which can utilize a wireless medium efficiently in communication of a mobile body.
[0011]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems. That is, the present invention is a wireless communication terminal,
Means for acquiring terminal location information of the wireless communication terminal;
Means for acquiring area location information of a service area by wireless media;
Means for determining whether the wireless communication terminal is within the service area from the acquired terminal position information and area position information;
And a control unit that is in a monitoring state in which the wireless medium is monitored when it is determined to be within the service area, and that is in a standby state when it is determined to be outside the service area. is there.
[0012]
Here, the service area using wireless media refers to a geographical area where service can be provided from the wireless media. This wireless communication terminal enters a monitoring state for monitoring the wireless medium in such a service area. In addition, outside the service area, the terminal 1 is in a standby state. For this reason, the terminal 1 can receive a service efficiently from a wireless medium. Here, receiving a service means, for example, receiving information periodically transmitted from a wireless medium, providing a function from a local communication partner, and the like.
[0013]
Preferably, the wireless communication terminal includes means for acquiring movement information of the terminal;
Means for extracting the service area of the wireless medium to be monitored from the acquired movement information, the terminal location information, and the area location information;
The control means may monitor the extracted wireless media.
[0014]
Here, the movement information is, for example, movement speed or acceleration. The service area of the wireless medium to be monitored refers to an area where access to or intrusion to the service area is predicted from the movement information, terminal position information, and area position information.
[0015]
The wireless communication terminal further includes means for predicting such a service area with the possibility of approach or intrusion, and the control means is configured to monitor the service area when the service area is in the vicinity. That's fine.
[0016]
Further, the present invention may be a method for causing a computer to execute any one of the processes described above. Further, the present invention may be a program that causes a computer to realize any of the functions described above. The present invention may also be a computer-readable recording medium that records such a program.
[0017]
Here, the computer-readable recording medium refers to a recording medium that accumulates information such as data and programs by electrical, magnetic, optical, mechanical, or chemical action and can be read from the computer. . Examples of such a recording medium that can be removed from the computer include a flexible disk, a magneto-optical disk, a CD-ROM, a CD-R / W, a DVD, a DAT, an 8 mm tape, and a memory card.
[0018]
Further, there are a hard disk, a ROM (read only memory), and the like as a recording medium fixed to the computer.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings of FIGS.
[0020]
1 is a conceptual diagram of a communication system according to an embodiment of the present invention, FIG. 2 is a state transition diagram of a terminal 1 mounted on the vehicle 20 of FIG. 1, and FIG. 4 is a data example of the service area location information database 7 for managing the location of the service area of the wireless media, and FIG. 5 is a flowchart showing the processing of the program executed on the terminal 1.
[0021]
<Concept of communication system>
FIG. 1 shows a conceptual diagram of this communication system. This communication system includes a terminal 1 mounted on the vehicle 20 and a communication facility that communicates with the terminal 1 by radio signals.
[0022]
Here, the communication equipment includes, for example, a roadside device 21 for a VICS service that provides information to a vehicle, a roadside radio device for ETC / DSRC that detects an intrusion of a vehicle into a predetermined area and provides a charging function and the like. 22 mag.
[0023]
The roadside device 21 is a communication device that emits a radio wave beacon or an optical beacon, and provides traffic jam information, road regulation information, parking lot information, and the like to the vehicle. Such information may be provided by FM multiplex broadcasting from the base station.
[0024]
The roadside wireless device 22 has a function of charging a usage fee without stopping the progress of the vehicle at a toll gate such as a toll road or a parking lot by wirelessly communicating with the terminal 1 mounted on the vehicle 20. provide.
[0025]
The terminal 1 is also called an in-vehicle device, and provides various functions, information, services, etc. to users in the vehicle. For example, the terminal 1 communicates with the roadside device 21, acquires information from the VICS, and displays it to the user. In addition, the terminal 1 communicates with the roadside wireless device 22 at a toll gate on a toll road, an entrance / exit of a toll parking lot, and provides a fee settlement function.
[0026]
However, the functions and services generally called ITS such as VICS and ETC / DSRC as described above are limited to a specific area. Such an area is referred to as a service area in the present embodiment. FIG. 1 illustrates a service area 21A for detecting a VICS radio wave beacon and a service area 22A for detecting an ETC / DSRC signal.
[0027]
The terminal 1 according to the present embodiment determines whether or not its current position is within such a service area, and monitors wireless media such as a VICS radio beacon and an ETC / DSRC signal when the terminal 1 is in the service area. On the other hand, when not in such a service area, the terminal 1 enters a standby state.
[0028]
In addition, the terminal 1 predicts the time point when it reaches the service area from the relationship between information such as its own moving speed and direction, and the distance to the service area. Then, the terminal 1 monitors the wireless medium from such a prediction time point.
[0029]
Note that the terminal 1 may provide the above functions as a single device. The terminal 1 may be any device that provides a single function, for example, an in-vehicle device for VICS communication, an in-vehicle device for ETC / DSRC, or the like.
[0030]
FIG. 2 is a state transition diagram of the terminal 1 mounted on the vehicle 20 of FIG. The terminal 1 transitions from a stopped state to a standby state by a user's startup operation, for example, power-on. The standby state refers to a state in which processing for determining whether or not the terminal 1 is within the service area or processing for predicting the arrival time at the service area is executed, and processing for monitoring the wireless medium is stopped.
[0031]
When it is detected that the terminal 1 is in the service area in the standby state, the terminal 1 transits to the monitoring processing state. In addition, when reaching the arrival point in the service area, the terminal 1 transitions to the monitoring processing state.
[0032]
Further, when it is predicted that the terminal 1 moves at high speed and repeats approaching and leaving the plurality of service areas within a predetermined time, the plurality of service areas may be set as monitoring targets.
[0033]
In the monitoring processing state, the terminal 1 issues a connection request to a wireless medium in the service area, for example, the roadside wireless device 22 of ETC / DSRC. Further, a connection request from the VICS roadside device 21 in the service area is detected. By transmitting such a connection request or receiving the transmitted connection request, the terminal 1 transitions to a communication state with the wireless medium.
[0034]
In the communication state, the terminal 1 receives provision of information from the VICS. For example, the terminal 1 receives traffic information and the like. Further, in the communication state, the terminal 1 settles the fee by ETC / DRSC.
[0035]
When the processing in the communication state ends, the terminal 1 returns to the monitoring processing state. This is due to, for example, a disconnection request from the terminal 1 to the wireless medium.
[0036]
Even in the monitoring processing state, the terminal 1 determines whether or not it is in the service area. When it is detected that it is outside the service area, the terminal 1 transits to a standby state and stops the wireless media monitoring process. Moreover, when there is no possibility of approaching the service area within a predetermined time, the monitoring process may be stopped.
[0037]
Furthermore, when a stop operation is performed in the standby state, for example, the power is turned off, the terminal 1 returns to the stop state.
[0038]
<Device configuration>
FIG. 3 is a device block diagram of the terminal 1. As shown in FIG. 3, the terminal 1 includes a vehicle speed pulse information acquisition unit 6 that receives vehicle speed pulses and detects vehicle speed, a GPS unit 5 that receives electromagnetic waves from satellites and acquires the current position of the terminal 1, and a road device for VICS. 21, a wireless processing unit 4 that communicates with the roadside wireless device 22 of ETC / DSRC, a power supply 3 that supplies power to the wireless processing unit 4, a control CPU 2 that controls the entire terminal 1, and a service CPU location information The service area position information database 7 is provided.
[0039]
The vehicle speed pulse information acquisition unit 6 receives a pulse signal generated by the rotation of the axle and calculates the vehicle speed, acceleration, and the like.
[0040]
The GPS unit 7 uses the electromagnetic waves from the artificial satellite to calculate information indicating where on the earth it is located, for example, the latitude, longitude, altitude, etc. of the current position.
[0041]
The wireless processing unit 4 includes an antenna and a high-frequency circuit, and performs communication with the roadside device 21 for VICS, the roadside wireless device 22 for ETC / DSRC, and the like.
[0042]
The service area location information database 7 holds information on the location of a service area where wireless media can be received and its existence range.
[0043]
The control CPU 2 controls each part of the terminal 1 and provides the function of the terminal 1. That is, the control CPU 2 executes a control program, and executes speed detection, acceleration detection, current position acquisition, service area position information search, and the like.
[0044]
In addition, the control CPU 2 determines approach or arrival to an area (or time zone) where the wireless media function, information, service, or the like can be received from the current position, speed, acceleration, and service area information. Then, the control CPU 2 instructs the wireless processing unit 4 to monitor the wireless medium by instructing power supply from the power source in the vicinity of such an area or time zone. Then, in response to a request from the user or a request from the communication partner, reception of VICS information, transmission of data to the ETC / DSRC device, and the like are executed.
[0045]
<Data structure>
FIG. 4 shows an example of data in the service area location information database 7 for managing the location of the service area using wireless media.
[0046]
Each row in the table of FIG. 4 corresponds to one record of this database and records information of one service area. As shown in FIG. 4, the record of the service area position information database 7 has fields of media, coordinate position, highway / general road identification information, area radius, valid / invalid / deleted.
[0047]
In the media field, the type of wireless media provided in the service area is described. For example, information such as VICS radio waves, ETC, DSRC, and VICS light is stored.
[0048]
In the coordinate position field, the latitude and longitude of the center position of the service area are described. In the present embodiment, the service area is defined by a circle centered on the center position. However, instead of this, the latitude and longitude of the diagonal position of the rectangle may be held.
[0049]
The identification information of the expressway / general road describes whether the wireless media of each service area is provided by the expressway facility or the general road facility.
[0050]
The area radius is the radius of the service area. However, the area radius is not necessarily required when the latitude and longitude of the diagonal position of the rectangle is held as the coordinate position. When the service area is defined by a rectangle, the latitude and longitude of one point on the rectangle, for example, the upper left point and the dimensions of the sides of the rectangle (the north-south direction and the east-west direction) may be held.
[0051]
In the valid / invalid / delete field, information such as the service area being currently in service (valid), service stop (invalid), or service area abandoned (deleted) is recorded.
[0052]
With this field, it is possible to manage information such as service suspension or abolition of the actual service area. Further, in the case of such cancellation or abolition, it is not necessary to delete the records of the database one by one, and the database management becomes easy.
[0053]
<Action>
FIG. 5 shows processing of a program executed on the terminal 1. As shown in FIG. 5, the terminal 1 is in a stopped state in the initial state (S1). When the user performs a startup operation, for example, power ON, the terminal 1 enters a standby state (S2).
[0054]
In the standby state, the terminal 1 searches the service area position information database 7 (S3). Further, the terminal 1 acquires current position information from the GPS unit 5. Further, the terminal 1 acquires the vehicle speed (speed, acceleration) from the vehicle speed pulse information acquisition unit 6.
[0055]
Then, the terminal 1 determines whether there is currently a service area in the vicinity. If there is a service area (service area is also referred to as a spot area) in the vicinity, the terminal 1 shifts to a monitoring process state (S4).
[0056]
In this case, when there are a plurality of service areas where the moving speed is high and the approach and the departure are repeated within a predetermined time, the plurality of service areas may be monitored.
[0057]
In the monitoring process state, in addition to the search of the service area information database 7 (S6), the acquisition of the current position, the acquisition of the speed and the acceleration, the wireless medium is also monitored.
[0058]
In that case, when the service area to be searched is limited, the service area may be searched in a region having a radius proportional to the moving speed with the current position of the terminal 1 as the center. That is, the search target area may be small when the moving speed of the terminal 1 is small and large when the moving speed of the terminal 1 is large. In this way, it is possible to reliably exclude and search for a service area that does not leak and is not likely to reach according to the moving speed.
[0059]
When there is a connection request from the user or a connection request from the communication partner in the monitoring processing state, the terminal 1 enters the communication state (S6).
[0060]
In the communication state, the terminal 1 receives various functions, information, or services from the wireless medium. For example, the terminal 1 receives traffic information from VICS or the like. Further, the terminal 1 performs fee settlement by ETC / DSRC. Furthermore, the terminal 1 may newly acquire service area position information (S7). The acquired service area position information is stored in the service area position information database 7.
[0061]
When the communication is completed, the terminal 1 returns to the monitoring process state (S4). As described above, even in the monitoring processing state, the terminal 1 executes processing for determining whether or not there is a service area in the vicinity. When the departure from the vicinity of the service area is detected in the monitoring state, the terminal 1 returns to the standby state (S2). Further, when a stop operation is executed due to power OFF or the like, the terminal 1 enters a stop state.
[0062]
As described above, the terminal 1 according to the present embodiment is in the vicinity of a service area where it is possible to receive functions provided by wireless media, information provided from wireless media, or services provided from wireless media. Determine whether or not. And the process which monitors a wireless medium in the vicinity of such a service area is performed. For this reason, the period of the monitoring process state for receiving the information from a wireless medium can be shortened.
[0063]
Therefore, it is possible to shorten the period of the radio signal reception process (reception operation of the radio processing unit 4 shown in FIG. 3) necessary for the monitoring process. In addition, power from the power supply 3 supplied to the wireless processing unit 4 can be saved. Further, the processing amount of the control CPU 2 that controls the power supply 3 and the wireless processing unit 4 can be reduced.
[0064]
For example, in an area where service from wireless media cannot be received, the wireless processing unit 4 and the power supply 3 may be stopped. In the same area, there are few cases where a plurality of service areas overlap. For this reason, the number of executions of wireless processing is leveled. In addition, the efficiency of wireless processing can be improved. In addition, the power consumption of the wireless processing unit 4 can be reduced.
[0065]
The terminal 1 can increase the detection accuracy of a communication request from a wireless medium and increase the possibility of reliable communication by performing monitoring processing in the vicinity of the service area.
[0066]
Further, when the wireless processing is stopped, the control CPU 2 can increase resource allocation to other processing. For example, resource vacancy due to the stop of radio processing can be allocated to application processing for fading and the like, and signal processing such as digital filter, and efficient resource allocation can be achieved.
[0067]
<Modification>
In the process of FIG. 5, the terminal 1 determines whether or not there is a service area in the vicinity from the current position, speed, acceleration, and service area position information. However, the implementation of the present invention is not limited to such a procedure.
[0068]
For example, the terminal 1 calculates a predicted time zone (arrival time and departure time from the service area) to enter a specific service area from the current position, speed, acceleration, and service area position information, and monitors at the arrival time The processing state may be entered, and the standby state may be returned at the departure time.
[0069]
In the above embodiment, as shown in FIG. 5, new service area position information is acquired in the communication state (S6) (S7). In this processing, position information of the next service area may be acquired. For example, a VICS road device installed along a road may deliver position information (position of the next road device, receivable range, etc.) of the next service area located in the traveling direction. In this way, it is possible to simplify the process of searching for location information of the next service area in the terminal 1.
[0070]
Further, as a method for obtaining the location information of the service area, for example, the service area may be received through broadcast media such as FM waves. That is, the location information of the service area may be broadcast for each area classified as the reach of the broadcast media, and the terminal 1 may receive the location information of the service area located in the vicinity of itself in each area. .
[0071]
In the above embodiment, the directivity of wireless media is not considered. However, for example, if the terminal 1 can acquire the position information of the transmission antenna of the wireless medium or the directivity pattern of the transmission antenna, the directivity of the reception antenna can be matched with the direction of the transmission antenna or the directivity pattern of the transmission electromagnetic wave. become. For that purpose, information indicating the position of the transmission antenna or information indicating the directivity pattern of the transmission antenna may be held in the service area position information database 7 shown in FIG.
[0072]
In the above embodiment, it is determined whether the terminal 1 is in the vicinity of the service area. In addition to such processing, it may be detected that the terminal 1 is traveling on a specific road, for example, an expressway. By detecting which road is being traveled, the terminal 1 can predict a traffic path. Therefore, the resource allocation to the wireless medium in the service area where the terminal 1 is unlikely to approach can be reduced, and the resource allocation to the wireless medium in the service area where the terminal 1 is likely to approach can be increased. Distribution is possible.
[0073]
【The invention's effect】
As described above, according to the present invention, wireless media can be used efficiently in mobile communication.
[Brief description of the drawings]
1 is a conceptual diagram of a communication system according to an embodiment of the present invention. FIG. 2 is a state transition diagram of a terminal 1. FIG. 3 is a device block diagram of a terminal 1. FIG. Example [FIG. 5] A flowchart showing processing of a program executed on the terminal 1 [Explanation of symbols]
1 Terminal 2 Control CPU
3 Power supply 4 Wireless processing unit 5 GPS unit 6 Vehicle speed pulse acquisition unit 7 Service area position information database

Claims (3)

Means for acquiring terminal location information of a wireless communication terminal;
Area position acquisition means for acquiring area position information of a service area by wireless media;
Means for determining whether a wireless communication terminal is within the service area from the acquired terminal position information and area position information;
Means for obtaining movement information of the wireless communication terminal;
Means for predicting an entry time and a departure time of the wireless media to be monitored from the acquired movement information, the terminal location information, and the area location information;
When it is determined that it is within the service area and when the predicted intrusion time is reached, the wireless medium is monitored, and when it is determined that it is outside the service area and when it is predicted to leave Control means that enters a standby state when the time comes,
With
The area position acquisition means acquires area position information of a service area located next in the traveling direction of the wireless communication terminal from the wireless medium when the wireless medium is in communication with the monitored wireless medium.
A wireless communication terminal characterized by the above. The computer installed in the wireless communication terminal
Obtaining terminal location information of the wireless communication terminal;
Obtaining area location information of a service area by wireless media;
Determining whether a wireless communication terminal is within the service area from the acquired terminal location information and area location information;
Obtaining movement information of the wireless communication terminal;
Predicting an entry time and a departure time of the wireless media to be monitored from the acquired movement information, the terminal location information, and the area location information;
When it is determined that it is within the service area and when the predicted intrusion time is reached, the wireless medium is monitored, and when it is determined that it is outside the service area and when it is predicted to leave A step that goes into standby when the time comes,
Obtaining the area position information of the service area located next in the traveling direction of the wireless communication terminal from the wireless medium when the monitoring wireless medium is in communication state;
The wireless communication method characterized by performing. To the computer installed in the wireless communication terminal,
Obtaining terminal location information of the wireless communication terminal;
Obtaining area location information of a wireless media service area;
Determining whether a wireless communication terminal is within the service area from the acquired terminal location information and area location information;
Obtaining movement information of the wireless communication terminal;
Predicting an entry time and a departure time of the wireless media to be monitored from the acquired movement information, the terminal location information, and the area location information;
When it is determined that it is within the service area and when the predicted intrusion time is reached, the wireless medium is monitored, and when it is determined that it is outside the service area and when it is predicted to leave comprising the steps of: a standby state when it becomes in time,
Obtaining the area position information of the service area located next in the traveling direction of the wireless communication terminal from the wireless medium when the monitoring wireless medium is in communication state;
A program characterized by having executed.

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